Nickel catalyst



Patented Dec. 12, 1944 ti e , NICKEL CATALYST Hans W. Vahlteich,Edzewater, and Ralph M.

Neal, Jersey Cit signments, to The assignors. by mesne as- Best Foods,'c.. New Yorlr,

N. Y., a corporation of New Jersey No Drawing. Application February .28,1942 Serial No. 432,828

' 7 Claims. (Cl. 252-224) This invention is concerned with theproduction of nickel catalysts and more particularly with the control ofthe particle size and other charac-. teristics of the nickel catalyst toprovide an improved product for use in the hydrogenation of vegetableoils. Itis especially concerned with the production of an improvednickel catalyst, the use of which results in a substantial saving in theamount of nickel required to satisfactorily hydrogenate vegetable oilsunder commercial conditions.

It has previously been known to produce nickel catalysts by decomposingnickel formate or other nickel salts of organic acids in an inertatmosphere to produce active nickel catalysts. Such procedures aredescribed, for example, in the copending applications of Borkowski andSchille,

Serial No. 342,446, filed June 26, 1940, and Serial No. 394,094, filedMay 19, 1941.

In the use of such procedures, in which the decomposition or reductiontakes-place at atmospheric or higher pressures, the product is in theform of very finely divided, amorphous particles so small as to approachsubmieroscopic particles and having an estimated diameter of. aboutmicron and it was considered that the smaller lower vacuums.

organic acid under a partial vacuum and prefer ably in an inertatmosphere. ,While some improvement has been noted with vacuums as lowas 5 inches of mercury, it is preferred to operate By following such aprocedure a very active nickel catalyst predominantly of particle sizesof about 2 to 10 microns, preferably 3 to 6 microns,

and with numerous particles up to 20 or 25 microns, can be prepared. Thereduction under vacuum should be controlled and limited so as to avoidreducing the particles to smaller sizes, since such further reductionwill cause them to lose their increased activity.

The decomposition or reduction of the catalyst may be better controlledby heating in a mixture of white mineral oil and vegetable oil. The useof white mineral oil alone results in a less active catalyst; withvegetable oil alone the reduction the particle size the more active thecatalyst would be, since it would present more external surface. Suchcatalyst may be used to advantage with a sorbent material, as describedin the above mentioned applications, but where it is necessary toproduce practically saturated oils, such, for example, as in theproduction of hard butter type oils having an iodin number of less thanone or in the production of saturated peanut oils having an iodin numberof 2 or less, it is necessary to add new catalysts frequently and thecatalysts recovered cannot be re-us'ed as much as is desired. Also, thehydrogenated oil will retain some of the finely divided catalyst whichcauses the oil to deteriorate more rapidly, on standing.

It is an object of the provide an improved procedure for producingactive nickel catalysts whereby particles ,of larger and controlled sizemay be formed. A further object is to provide a procedure by which suchlarger sized particles are more active or more present invention to istoo vigorous and also difflcult to control. We have found that the useof U. S. P. neutral white mineral oil (for example, one having a.viscosity of 335 to 345 Saybolt at 100 F-. a specific gravity of .885 to.895 at F. and a boiling point range of 560 to 790 F.) in the amounts ofabout 4 to 14 times the weight of nickel present in the nickel salt, andpreferably about 10 times the weight'of nickel present, is satisfactory,although smaller or larger amounts may be used under certaincircumstances. Also, other neutral white mineral oils may be used,preferably the higher boiling point ones, for example, within theboiling point range of 615 to 890 F. The vegetable oil may be about M4to. 1 part by weight per 1 I part of nickel in the nickel salt and-isprefers effective in the hydrogenation of vegetable oils.

position or reduction of the nickel salt ofan l6 ably about V2 part ofvegetable oil to 1 part of nickel. A suitable mixture is one such as togive 10% nickel (calculatedas metallic nickel), 5% vegetable oil andmineral oil. The vegetable oil used in admixture with the mineral oilvehicle is preferably the same'as or at least compatible with the oil tobe hydrogenated with the catalyst. For example, a portion of thehydrogenated oil from a previous hydrogenation may be used for thispurpose. However, the amount used is so small in-comparison with theamount of oil to be treated with the catalyst that the selection of asuitable vegetable oil is not difficult,

' drogenation of vegetable oils.

As a specific example of our improved process, about 300 grams ofpowdered commercial nickel formate was mixed with about 720 grams ofwhite mineral oil and about 42 grams of refined cottonseed oil. Themixture was then agitated and heated to about 450 F. in a nitrogenatmosphere, and at about atmospheric pressure, in order to drive off thewater of crystallization of the nickel formate. With the particularapparatus used, this required about one hour.

The vacuum was then applied and the flow of nitrogen gas continued, butwas decreased to give a vacuum of about 15 to 20 inches of mercury. Thetemperature was raised to about 475 F. and the material was held at thattemperature for aboutlO to 15 minutes, or until substantially all thegaseous products of decomposition had been released, and was then raisedto about 520 F. and held at that temperature for about to minutes. Thetemperature was then reduced quickly to below about 475 F., below whichit could be further cooled without particular care.

The resultant product was cooled to about 200 F. and mixed with anactivated carbon sorbent in the proportions of about 15 times the amountof active nickel present. The mixture was then added to the oil to behydrogenated and the hydrogenation carried out in the usual manner. Forexample,

point of approximately 140 to 145 F. and. an iodin number of 1 to 5, orfor the hydrogenation of hardbutterf type oils (such as palm kernel oil,coconut oil, babassu oil or similar oils suitable for use in preparing"hard butters) to an iodin number of less than 2, the catalyst may beused in the proportions of about .05 to .08% of metallic nickel basedupon be hydrogenated. The hydrogenation may be carried out at atemperature of about 350 to 380 F. with rapid agitation. After thehydrogenation is completed, the catalyst and activated carbon may bereadily filtered out and may be re-used in a subsequent operation,sufficient fresh catalyst being added to make up for any loss. Oicourse,when the hydrogenation of the oil is less drastic (to a higheriodin number), smaller quantities of the catalyst will be required. Forinstance, in hydrogenating cottonseed oil to an iodin number of 60 to70,- only about one-tenth of this amount of catalyst would be required.

The relatively small amount of mineral oil associated with the activecatalyst to be added to the oil to be hydrogenated may be removed, ifdesired, by filtration to separate the main portion of the liquid fromthe catalyst or it may be separated by gravity settling followed bydrawing off the clear oil fraction composed principally of mineral oilwith a small amount of vegetable oil in it. Such procedures to separatethe mineral oil may be unnecessary, however, since, in any event, it isnormally substantially, if not completely, removed during the subsequentdeodorizing of the hydrogenated vegetable oil.

The activated carbon itself serves as a sorbent and filter aid but ifused alone it may compact too much in the filtering operation. It ispreferred, therefore, to also use a filter aid, such as diatomaceousearth (filter cel) or fullers for the hydrogenation of peanut oilsubstantially to saturation, that is, to a melting the amount of oil to-2,ses,1as

- reduction of earth, to give the desired porosity to the filter cake.The filter aid may be added before the the catalyst, but this is notnecessary and, in fact, it is preferred to add it after the reduction toactive nickel, since if present during the reduction it interferes withmicroscopically determining the sizes of the nickel particles, whichdetermination serves as an important indication in the control of thereduction of the catalyst.

The above example is given as illustrative and may be altered to meetvarying conditions and requirements. For example the nickel formate maybe heated at temperatures of 400 to 450 F. in driving of! the water ofcrystallization. Also, if desired, vacuum may be applied in this step,due care being taken in the choice of equipment, etc. to avoid excessivefrothing. The heating to decompose and drive off gases of decompositionmay be carried out at temperatures of 4'70 to 480 F. for 10 to 45minutes, depending upon the time required to remove the gaseous productsof decomposition. The heating thereafter is preferably at temperaturesof 500 to 525 F. for 5 to 25 minutes. Higher temperatures, for exampleup to 550 F., have been used for a shorter time,

but the results were not as satisfactory as with .mechanically heldtherein and those formed during the reaction, to be drawn out of theparticles before the internal pressure becomes such as to cause theparticles to explode violently and disintegrate into small particles.There is a critical temperature at which the organic salt decomposes andthe vacuum appears to increase the temperature range over which thedecomposition takes place and also somewhat lowers the temperature ofthe decomposition. The drawing out of the gases apparently increases theavailable active surface area of the catalyst. It also appears to retardor control the deformation of the particles and permits them to formparticles with enlarged surfaces, much like in the popping of pop-corn,but without such deterioration as would result in bursting the particlesinto small bits; thus leaving active catalyst particles of greatlyincreased surface area and of sufficient ruggedness to stand up andmaintain their particle sizes for a longer period. The characteristicform of the product is readily observed under a high powered microscopeby first diluting the sample of reduced catalyst with a suitable oilsolvent such as carbon tetrachloride; the active nickel particles appearas distinct, sharp cornered and apparently cubical structures,resembling in form sodium chloride crystals.

The form of thecatalyst is important particularly for use in severehydrogenations, for example, in hydrogenations to a very low iodinnumber or where the removal of the last portion of the unsaturation isimportant, since the difficulties in hydrogenation increase as the iodinnumber is lowered for a complete saturation.

By-using a catalyst prepared as described, a given weight of the activecatalyst will successfully hydrogenate a greater weight of vegetable orother-fatty oil than with catalysts prepared particular oil toward byprior practices. Because of the larger particle ing the filteringoperation. The ruggedness of the particles will permit the repeatedreuse of' the catalyst in severe 'hydrogenations, such as thehydrogenation of peanut oil having an iodin number of 90 to 95 down toan iodin number of about or less, or as in the preparation oi "hardbutter" type oils; The catalyst may also be used to advantage in lesssevere hydrogenations, such as the hydrogenation of cottonseed oilhaving an iodin number of about 105 to 110 down to an iodin number ofabout 70, as required in the preparation of margarine oil or in thepreparation of oils for other uses.

The vacuum applied during the decomposition of the nickel organic saltmay be controlled by varying the input of nitrogen or other inert ornon-reducing gas into the vessel in which the catalyst is beingdecomposed or reduced. For example, if the apparatus used is such that ahigher vacuum is obtained, this maybe reduced by introducing nitrogen orother inert gas, for example, as argon and helium, etc. into theapparatus. The. flow of nitrogen or other inert or non-reducing gasthrough the apparatus also helps to'scrub out the gaseous products ofreduction. The nitrogen or other inert or nonreducing gas is used,instead of a reducing gas, to decrease the vacuum and to scrub out thegaseous products of the reduction, in order to better control the extentof the decomposition and resultant breakdown oi the particles. The useor a reducing gas for this purpose causes the reaction to go too farwith a resultant breaking down of the particles into smaller and lessactive particles.

It is obvious that many other variations may be made in utilizing ourimproved procedure and such variations may require changes in thedetails of operation described in the illustrative examples. Forexample, the invention may be utilized in the preparation of activenickel catalysts from other nickel salts of organic acids that decomposewith the formation of hydrogen. For instance, nickelacetate, nickeloxalate, nickel benzoate, etc. may be used for this purpose. Suchdecomposition of the organic salt with formation of hydrogen providessuflicient hydrogen to maintain the desired reducing atmosphere so nohydrogen, as such, need be added.

The temperatures and times of the decomposi tion or reduction of the,nickel organic salt may be varied, depending upon the particular saltused and upon the equipment and details of the procedure employed. Theconditions or decomposition of the nickel organic salt, and particularlythe temperature, time and per cent. of vegetable oil in the mineral oilvehicle, should be selectedso as to quickly decompose or reduce theorganic salt, but should be such as to sufllciently retard the reactionto-permlt control and avoid excessive subdivision of the particles. Thespeed of the reaction may be cut down, if desired, by

using a higher percentage of mineral oil mule oil vehicle. in commercialoperations it is usually prelerred t0 operate at; 8'8 10W 8, temperatureand under other conditions and may be somewhat vol-' Vacuum, and as'nlgh a percentage oi vegetable oil, asis practicable. 'lne prelerredmaximum temperatures ln this process are 10 to so r. lower, or the timesare 15 to minutes shorter, than in prior practices in the reduction ornickel organic salts without the use Of a vacuum as described herein.

Although it is preferred to use a mixture of vegetable and mineral oilas described a ove for the liquid vehicle in which to decompose thenickel salt, the mvent on may also be used in the decomposition ofnickel salts in other heat transferring liquids, such, l'or example, asin a mixture or mlneral oil and animal rats or other glycerldlc rats andoils or a mixture or mineral oil and iatty acids. It may also be used tosome advantage with decompositions in mineral oils alone or vegetable orannual, etc. oils or fats or Iatty acids alone or in other liquids thatare not deleterious t0 the nickel catalyst and that are nor, excessivelyvolatile under the conditions or operation. such a vehicle will berezerred to in the claims as a non-aqueous, non-volatile liquid vehicle,although it is understood that it may be volatile atlle under theconditions or use, provided that not too much or the vehicle hedistilled during the processing described herein. In using the term oilin the appended claims, it is intended dill iii?! to include solid oilssometimes referred to as fats, and-in using the term fatty oil it isintended to include vegetable, animal and fish and other glyceridicoils, as well as iattv'acids of such oils- Other variations in the useor" the invention will be obvious to those skilled in the art. The termsused in describing the invention have been used in their descriptivesense and not as terms of limitation and it is intended that alleduivalents oi the terms used be included within the scope or theappended claims.

We claim: a

i. A method for preparing an active nickel catalyst comprising heating anickel salt of an organic acid in a mixture or white mineral oil and. afatty oil containing about d to ld parts by weight oi white mineral oiland about V to 1 part by weight of fatty oil to one part of nickel tode= 7 catalyst comprising heating nickel formats in a mixture oi whitemineral oil and vegetable oil containing about i to M parts by weight ofmin eral oil and about $4 to 1 part or vegetable oil to 1 part of nickelto temperatures of about 450 to 550 F. in a non-reducing atmosphere andunder a vacuum of about 10 to 25 inches of mercury.

3. A method for preparing an active nickel catalyst comprising heatingnickel formats in a mixtune of white mineral oil and vegetable all con--taining about 10 parts by weight of mineral oil and 3 2 part oivegetable oil to 1 part of nickel to temperatures of about 450 to 520 F.in an inert atmosphere and under a vacuum of about so inches of mercury.

4. A method for alyst comprising heating nickel formate in a mixture ofwhite mineral oil and vegetable oil containing about 7 to 14 parts byweight of white mineral oil and about V to 1 part or vegetable oil toone part of nickel to 400 to 450 gen atmosphere to drive oi! water orcrystallizapreparing an active nickel cattion, thereafter heating it to470 to 480 F. in a nitrogen atmosphere and under a vacuum of about 10 to25 inches of mercury to drive of! gas-- eous products of decompositionand thereafter heating it to 500 to 525 F. in a nitrogen atmosphere andunder a vacuum of about 10 to 25 inches of mercury.

5. An active nickel catalyst prepared by heating a nickel salt of anorganic acid in a mixture of white mineral oil and a .tatty oilcontaining about 4 to 14 parts by weight of white mineral oil and about/4- to 1 part by weight of fatty oil and one part of nickel todecomposition temperatures under a vacuum of about 10 to-25 inches ofmercury.

6. An active nickel catalyst prepared by heating a nickel formate in amixture of white mineral oil and vegetable oil containing about 7 to 14parts by weight of mineral oil and about A. to 1 part of vegetable oilto 1 part of nickel in an inert atmosphere to decomposition temperatures between 450 to 550 F. under vacuums of about 10 to 25inches ofmercury to provide particles predominantly of about 2 to 10 microns.

'7. An active nickel catalyst prepared by heating a nickel formate in amixture containing about 10 parts by weight otwhite mineral oil and partof vegetable oil to 1 part of nickel to a temperature between 450 to 550F. in a non-reducing atmosphere and under a vacuum of about 20 inches ofmercury to provide particles predominantly of about 3 to 6 microns.

HANS W. VAHLTEICH. RALPH H. NEAL.

